Questions tagged [star-formation]
Questions related to the physical processes involved in or to the observations of the process of forming a star.
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Can stars be born giants?
My understanding is that giant stars are formed when they leave the main sequence and begin to burn elements heavier than hydrogen. Can some stars, however, be born as giants or do all stars start off ...
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How certain is the Sun's classification?
Curious Question here.
How do we know the Sun is a G-Type Star?
Our sun (Classed as G2V) apparently lies around the 5,780 Kelvin. Yet NASA generalizes it as 6,000 K- and is apparently white even ...
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Is it possible for a star cluster to be composed of main sequence stars?
From what I hear about globular clusters, they are primarily composed of very hot giant stars, which are not the most conducive for life as we know it.
Main sequence stars like our own, due to their ...
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What kind of nebula was the Sun formed from?
I was just wondering what type of nebula did the Sun form from because mainly there are 5 categories: emission nebulae, reflection nebulae, dark nebulae, planetary nebulae, and supernova remnants, so ...
user47732
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How do I code the formula for the minimum mass of a stellar fragment from Whitworth & Stamatellos, 2006?
I was researching the formation of brown dwarfs, and I stumbled into the paper "The minimum mass for star formation, and the origin of binary brown dwarfs", and I am attempting to code a ...
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What is the average and the median mass and luminosity of a star?
I've heard in many places that the Sun is an average star, but in Wikipedia it says that about 75% of stars are M-type stars that are way less massive and fainter that the Sun. So how massive and ...
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Why are the Pillars of Creation pillar-shaped?
The Pillars of Creation have a strong directional sense. They are referred to as "pillars" and another question asks how "tall" they are. Naively, it looks as if there is a source ...
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Star formation - Is it just gas accumulation or does dust also play a role?
Inspired by the question, Are heavy elements equally distributed throughout the Solar System?, with a little further inspiration from this one as well, Star formation analogy, particularly the answer ...
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Could a quasi-neutron-star exist between the maximum mass of a star and the mass of a quasi-star?
A quasi-star is a hypothetical supermassive star that is so heavy its core collapses into a black hole as it is still forming. The matter accreting into the black hole then generates radiation ...
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Has anybody measured the mass density profile $\Sigma = \Sigma (r)$ of a protoplanetary disk? (when $r<1$ AU)
I've been trying to find research articles where the mass density distribution $\mathrm{\Sigma = \Sigma(r)}$ is determined for protoplanetary disks, when $r<1$ au. For instance:
Here A. Miotello, ...
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Has the birth of a new star ever been observed (scientifically speaking)?
Not too long ago, Pluto was "demoted" because it no longer met the criteria for being a full-fledged planet. Similarly, in order to be classified as a star (and not, say, a proto-star, or ......
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How can a brown dwarf be more massive than a star?
SDSS J0104+1535 is about 90 times more massive than Jupiter, making it the heaviest known brown dwarf. EBLM J0555-57Ab has a mass of about 85.2±4 Jupiter masses, or 0.081 Solar masses.
I am confused. ...
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What happens if supernova undergoes in tightly close multi stars system
I do wonder in a tight or close orbital binary stars or multi stars system, if one stars undergoes supernova and that blast can lead another stars in the system to become supernova, too?
Is there ...
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Difference between NSBH and BHNS mergers
What's the difference between Neutron Star-Black Hole Merger (NSBH) and Black Hole-Neutron Star Merger (BHNS)? Are they the same names for the same events or is there any difference between them?
I ...
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Why does the gas cloud collapse in regions of high density?
Stars form when gas cloud collapse under gravity, becoming hot and subsequently initiating nuclear fusion. I have read that the collapse is triggered by density fluctuations, where regions of high ...
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What is the relation between Kelvin-Helmholtz timescale and free-fall timescale?
What is the actual difference between these two timescales? Both of these timescales define the time for collapse when there is only gravity. Also, what does it mean by saying Kelvin-Helmholtz ...
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Massive star formation
Imagine we have a stellar cloud sufficiently massive to generate N high mass stars, what is the reason for this scenario not to happen? Because I know that when the jeans instability happens a star is ...
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what is the difference between Composite Stellar Population and Galaxy Spectral Energy Distribution?
I am reading Conroy et al. (2013), an extensive review on Stellar Population Synthesis technique, and I really can't get the difference between Composite Stellar Population and Spectral Energy ...
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The reason for an exoplanet density increase of planets closer to a star
From the NASA exoplanet archive system it can be seen that in the range of $0.02-0.06~\text{AU}$ distance an exoplanet is to its star, as distance drops down, the planet density increases linearly:
A ...
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Why is the composition of the sun so distinct from that of earth?
Given that the sun is – in astronomical distances – quite close to the earth, why are the two composed of such distinctly different substances?
Sun Composition
Hydrogen 74.9%
Helium 23.8%
Oxygen ~1%
...
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What would be the product between the collision of a white dwarf and a main sequence star?
Would this ever happen? If it would, what kind of star/supernova would this create? Does it depend on the mass of the main sequence star?
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Can distribution of stars / planets formation be a long-tailed one?
We know that peak of star formation already passed
10.1146/annurev-astro-032620-021910
and it looks like peak of planet formation occurred slightly after formation of Earth
10.1017/S1473550415000208
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Why can't 'dead' galaxies start forming stars again if they merge with another, 'active' galaxy?
I heard Matthew O'Dowd mention on PBS Space-Time that dead galaxies cannot start re-forming stars even if they collect gas and/or dust from elsewhere, or even merge with another galaxy....
Why? And ...
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Has Altair flung off its planets by rotation?
This might be a dumb question, but would it be possible that during the star Altair's formation, the centrifugal forces became so large that its planets were flung away into space?
Or could a passing ...
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Is there a metallicity threshold past which star formation is impossible?
I've learned that metallicity is a very important factor to consider when talking about a star's formation and lifecycle. That gets me wondering whether a high enough metallicity could prevent the ...
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How to account for the effect of Star Formation History on the inferred Stellar Initial Mass Function?
I am studying a paper The effect of star formation history on the inferred stellar initial mass function and trying to reproduce the given results.
According equation (1) in the paper, the inferred ...
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Why does rotation prevent the further contraction of the cloud?
In the book Horizons: Exploring the Universe (2018) by M.Seeds and D.Backman, chapter 9, page 170-171, it states that:
At least four factors resist the
compression of an interstellar gas cloud, and ...
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Could our Sun be the product of an ancient stellar collision?
The canonical model for the formation of the Solar System involves the gravitational collapse of a nebula into (perhaps) several stars across several light years. Is it possible that two or more of ...
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How much matter was ejected when the Solar System formed?
Assuming the accretion disk model for the formation of the Solar System, the most important problem, according to wikipedia, is "how the material, which is accreted by the protostar, loses its ...
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What is the birth of a star like? [closed]
Here's what I'm curious about. So this hydrogen gas collects and at some point, it eventually becomes a star. What does that process look like? If you were there as a witness to the formation of a ...
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Galactic orbits and distance between stars
In the context of whether or not nearby stars were created from the same nebula, this answer states:
imagine two stars with very similar orbits, one with a period of 200 million years and the other ...
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After a supernova, why don't new stars coalesce with higher heavier element content?
May be a beginner's question but I couldn't find the answer anywhere.
Given a supernova event and the cloud left by it, why does a new star coalesce with a disproportionally higher hydrogen(and helium)...
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Are new stars less pure as generations go by?
If stars are primarily made of hydrogen, which is then burned to helium, and then on and on and on down the chain until you either reach iron, or in extreme cases much heavier metals, this then ...
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How many generations of stars can be formed in the Stelliferous Era?
As in general case, stars are formed from nebula which in some case itself is the result of a supernova.
Also stars need hydrogen to become a star (to do nuclear fusion), but stars consume hydrogen in ...
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Origin as binaries and multiple system
The majority of hot stars originate as binaries or multiple systems. How is it with the cooler spectral types? Are they usually born as single stars?
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Do stars made by universe getting smaller or larger in mass? [closed]
Do stars made by universe getting smaller or larger in mass compared to stars made 180 million years after the Big Bang? If they are getting smaller, is this due to the fact that the universe is ...
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How can you tell the rough phase of star formation a star is in from the current radius and mass of the star?
This question is really bothering me since I'm getting mixed thoughts. The masses of the stars in question are 0.92 solar masses and 0.29 solar masses. The diameters are 1,400,000 km and 750,000 km ...
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Relation between absolute magnitude of UV and star formation rate
I surfed the internet and searched a lot of sites,
so far I got this
but unable to find the formula which relates only Muv and the Ψ as I don't know the value of parameters Auv and μ(z).
If there ...
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Why do stars rotate slower than they're expected to?
Due to conservation of angular momentum, I thought most stars would be spinning extremely fast because they have a relatively small diameter. However, it turns out that this is not true and most stars ...
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Will the Sagittarius A* Black Hole eventually swallow the entire Galaxy?
In one of his interviews, Sir Roger Penrose mentioned that when the Milky Way and the Andromeda galaxies eventually "collide" and merge into one, their super-massive black holes will also ...
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How can many stars be formed from the remains of one supernova?
A supernova is the explosion of a single star; so how is it that thousands of stars can "be born of" that one explosion (presumably only using the unspent fuel / lighter elements of the ...
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Is the magnetic field strength of a star predictable from mass, composition, age and angular momentum alone?
This answer to Which stellar properties can we describe as “first principles” in which we can derive the rest? contains an intriguing bit:
That states that composition and mass are the two key ...
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Galactic winds/outflows: why and how are they detected via blueshifted absorption lines in spectra?
I know that galaxies can eject gas due to supernovae, accreting black holes, etc. These galactic "winds/outflows" are often defined/detected observationally using blueshifted absorption ...
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Are metallicities of molecular clouds lower in the outskirts of the galaxy?
(this question was originally posted in an answer by user PSR-1937-21 to another post. I find it an interesting one, but since they don't seem to be active anymore, I'm posting it to see if somebody ...
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Why does a hot cloud need more mass to collapse?
I was wondering why does a hot cloud need more mass to collapse than a cold cloud to form a protostar? Is it because there's a higher thermal pressure inside the hotter cloud than it is in a colder ...
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Is it only possible to look at solar systems with stars at least as old as ours to be able to find intelligent life?
Assuming the speed it takes to development intelligent life is the same in all solar systems, would we need to look at exoplanets with stars as old or older than ours to find intelligent life? A young ...
user31880
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Supernova impact on Protostar formation
What would be the impact on the formation of a new star (protostar) when a nearby star (within 10 LY) goes supernova? Will the force of the explosion (once it arrives in the Molecular Cloud where the ...
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Why aren't there blue elliptical galaxies or yellow spiral galaxies?
Elliptical galaxies are universally old and yellow; about three-quarters of all ellipticals have no significant star-forming gas or dust left, and even the quarter or so of ellipticals that are still ...
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In Orion, how close in local distance are the closest of the member stars?
All the members of Orion are within the Milky way, and some of them look pretty close to a neighbor. And could the bow* be an effect similar to the Radcliffe Wave?
*shield
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Why does the star formation rate correlate with the total stellar mass in star forming galaxies?
The so-called "Main Sequence" of star-forming galaxies (e.g., Brinchmann et al. 2004; Noeske et al. 2007) clearly points to a linear relation between the stellar mass of galaxies and their star ...
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